Roller tables

ABSTRACT

A roller table is described having a frame with a longitudinal wall on which a number of bearing casings are rigidly mounted. Each bearing casing has a pair of parallel lugs projecting at right angles to the bearing axis and each formed with an aperture. The lugs straddle the top edge of the longitudinal wall which is also formed with an aperture and a pair of wedges extend through the apertures in the lugs and in the longitudinal wall. A tension bolt is provided for tightening the wedges and a strong compression spring is interposed between a nut on the bolt and the wedges to maintain tightness of the wedges even after wear of the contacting surfaces of the wedges, the wall and the lugs. The spring is arranged to be compressed by a hydraulic thrust device temporarily attached to a free end of the bolt. The nut is then tightened and the hydraulic device removed.

United States Patent Sack [451 May 23,1972

[54] ROLLER TABLES Primary Examiner-Charles W. Lanham [72] Inventor. Ernst Theodor Sack, Hosel, Germany Assistant Emmmer E M. Combs 73 Assignee: Maschinenfabrik Sack GmbH, Dusseldorf- AlwmeyMGlew and Toren Rath, Germany [57] ABSTRACT [22] Filed: Sept. 16, 1970 A roller table is described having a frame with a longitudinal PP NOJ 72,763 wall on which a number of bearing casings are rigidly mounted. Each bearing casing has a pair of parallel lugs projecting at right angles to the bearing axis and each formed with [30] Forelgn Apphcauon Priority Data an aperture. The lugs straddle the top edge of the longitudinal Sept. 20, 1969 Germany ..P 19 47 765.7 wall which is also formed with an aperture and a pair of wedges extend through the apertures in the lugs and in the lon- [52] U.S.Cl ..72/251 gitudinal wall- A nsi l is pr i e for tightening the [5 l Int. Cl ..B2lb 39/20 wedges and a Strong compression spring is im'fl'posed between 58 Field of Search ..72/199, 227, 237, 250, 251, a nut Oh the bolt and the wedges to maimain tightness of the 72/252; 193/35; 308/236 wedges even after wear of the contacting surfaces of the wedges, the wall and the lugs. The spring is arranged to be 56 R f C-ted compressed by a hydraulic thrust device temporarily attached 1 e erences I to a free end of the bolt. The nut is then tightened and the UNI ED STATES PATENTS hydraulic device removed.

3,345,850 10/1967 Sack et a1. ..72/251 3 Claims, 3 Drawing Figures PATENTEnmvzamz 3,664,167

sum 1 [IF 2 IN VEN TOR ERNST THEODOR SACK BY 7 gm 0/270 M ATTO R N EYS FIG.3

y ,5 5 2 I! 10 1/777! 11. 17 19 16 1/) A0 INVENTOR ERNST TH EODOR SACK MCW 0/ m ATTOR NEYS ROLLER TABLES The rollers of rolling mills, particularly cogging mills, are subjected in operation to violent impact stresses which are transmitted through the bearings of the rollers to casings which hold the bearings and which are mounted on a supporting frame of a roller table. Whereas in the case of comparatively lightly loaded roller trains the casings can be attached to the framesimply by bolting, this method gives trouble under high loads, the bolts working loose or rupturing. Although the difficulty has been partly overcome by using wedges, nevertheless under really severe conditions even this solution is not entirely satisfactory.

An attachment using wedges is described for example in the British Pat. specification No. 1,069,295. In this arrangement each bearing casing has a pair of parallel lugs which are perpendicular to the bearing axis and which straddle the top edge of a longitudinal wall forming part of the frame. The lugs have apertures which register with an aperture in the wall and are clamped tightly to the wall by wedging devices which extend through the apertures in the lugs and through the aperture in the wall. The wedges are tightened between edges of the apertures in the lugs and an edge of the aperture in the wall, by a tension bolt for example, to force the casing against the top edge of the wall.

This arrangement is better than simply bolting the casing to the wall, but under extremely high impact loads deformations of material occur and in the course of. time the wedging devices become loose. The elastic strain of a tension bolt is insufficient to take up the slack resulting from the deformations. As soon as the casing works loose, damage follows rapidly.

In accordance with the present invention, a roller table comprises a compression spring being interposed between the nut and the wedging device and being arranged to be compressed by a hydraulic thrust device temporarily attached to the bolt before tightening of the nut. With this arrangement, the attachment of the roller bearing housing to the longitudinal frame wall does not work loose even after considerable deformations of material have occurred.

The spring is preferably in the form of a package of strong plate springs and it must provide enough spring travel to ensure that the wedge remains locked in place by its wedge action even after deformations have occurred. This travel is greater than can be provided by the tension bolt alone. In the presence of deformations tending to loosen the wedge the spring tightens the wedge further so that the wedge actions is constantly sustained, holding the bearing casing firmly clamped to the frame wall.

The initial compressing of the spring by hydraulic pressure allows a far higher thrust to be applied than could be obtained merely by screwing up the nut. The thrust which can be applied by screwing up a nut is limited by friction. In the roller table according to the invention the spring is compressed by hydraulic pressure, the nut being merely tightened up afterwards to hold the spring compressed.

The hydraulic device, for compressing the spring, can be quite simple. In one example, the hydraulic device consists of a block screwed on to a free end of the tension bolt, the block having an annular groove in which an annular piston sleeve slides which can thrust, under the applied pressure, against the spring, so as to compress it, the piston sleeve having an opening in its side wall, to give access to the nut.

One example of a roller table in accordance with the invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a partly sectioned view showing a roller bearing casing mounted on a frame wall, the parts being shown in their positions before locking a wedging device;

FIG. 2 corresponds to FIG. 1, but shows the wedging device during tightening; and,

FIG. 3 also corresponds to FIG. 1 but shows the wedging device after tightening.

Of the roller table, FIG. 1 shows only a casing 1 which contains the bearing for a roller 2, which is represented in the drawing merely be its end, which has the customary conical shape. The casing l is mounted on the upper edge of a frame wall 3. The casing 1 contains the bearing for the roller 2, details of the bearing not being shown because these details are a part of the state of the art and have already been adequately described, for example in the British Pat. specification No. 1,069,395, which has been mentioned above.

The housing 1 sits astride the top edge of the frame wall 3, retained in position by two lugs 6 and 7, with the help of lateral spacer pads 4 and 5. The casing 1 is anchored to the frame wall 3 by a pair of wedges 8 and 9, which are inserted through apertures 10 in the fork arms 6 and 7 and through a slot or drilling 11 which passes through the frame wall 3. The wedge 8 is fixed stationary in the lugs 6, 7 by retainer projections 12, 13, which fix this wedge 8.in position so that it cannot shift lengthwise. The wedge 8 therefore acts as though it is of one piece with the lugs 6, 7 and in principle there could be used instead of a wedge 8 wedge shaped surfaces in the fork arms 6, 7, these surfaces sloping in agreement with the sloping wedge surface F of the wedge 8. However it is more convenient to use an inserted wedge 8, for ease in manufacture, rather than machining sloping surfaces in the lugs 6,7.

A tension bolt 14 is inserted lengthwise through the two wedges the lefthand end of the tension bolt 14, as shown in FIG. 1, has a retainer head 16 at one end which bears against the end face of the root of the fixed wedge 8. The other, free end of the tension bolt 14 is externally threaded.

On the free end of the tension bolt 14 a compression spring 17 is mounted, which bears against the end face 18 of the root of the mobile wedge 9. A thrust pad 19 thrusts against the outer end of the compression spring 17. A nut 20 is screwed onto the outer end of the tension bolt 14 and thrust, when tight, against the outer face of the thrust pad 19. When the parts are in the positions shown in FIG. 1 the nut 20 is not drawn tight, that is to say it has been screwed on to the tension bolt 14 only finger tight.

The compression spring 17 is a strong spring and preferably consists of a package of plate springs. To lock the wedges together the strong spring 17 is compressed by a powerful thrust applied by a hydraulic system which is represented diagrammatically in FIGS. 1 and 2. As already explained, the thrust applied to the compression spring 17 is a good deal higher than what could be obtained merely by tightening the nut 20. The hydraulic system consists of a block 21 screwed on to the outer end 15 of the tension bolt 14. The block 21 contains an annular cylinder groove 22 (compare FIG. 2) in which works an annular sleeve piston 23, which has an aperture 24 in its side to give access to the nut 20. The cylinder groove 22 can be connected to a source of hydraulic pressure 27, for example a hydraulic pump, through a duct 25 and a pipe 26.

The device is assembled as follows. After mounting the bearing casing l astride on the frame wall 3 the two wedges are inserted and the tension bolt 14 is inserted through them. The spring 17 and the thrust pad 19 are mounted on the end of the tension bolt 14. The nut 20 is screwed finger tight up against the thrust disc 19. The block 21, with its piston sleeve 23, is screwed on to the outer threaded end 15 of the tension bolt 14, so that the base 28 of the piston sleeve 23 rests against the outer face of the thrust disc 19. The parts are now in the positions shown in FIG. 1.

With the nut 20 screwed up only finger tight, as already mentioned, a considerable hydraulic pressure is applied by the pump 27 to the annular cylinder groove 22, thrusting the sleeve 23 pistonwise towards the left, compressing the spring 17, so that the spring 17 becomes highly prestressed. It should be emphasized that the compression applied to the spring 17 in this way is much greater than what could be applied merely by tightening up the nut 20.

With the spring 17 compressed under the high thrust which has been applied hydraulically, there is now a gap between the nut 20 and the outer face of the thrust disc 19, as shown in FIG. 2. A tool is inserted through the opening 24 in the side wall of the piston sleeve 23, and the nut 20 is tightened up, to take up the gap between the nut and the thrust disc 19. The

tool takes purchase in blind holes 29 in the side wall of the nut 20. Finally, with the nut now resting in firm contact with the outer surface of the thrust disc 19, the hydraulic pressure is released and the hydraulic parts can be unscrewed and removed, leaving the assembly in the final state represented in FIG. 3.

I claim:

1. A roller table comprising a supporting frame, an apertured longitudinally extending wall on said frame, a number of casings holding bearings each receiving rollers for rotation in said bearings a pair of parallel apertured lugs for each bearing casing disposed perpendicularly to the bearing axis and disposed one on either side the top edge of said longitudinally extending wall with said apertures of said lugs in register with an aperture of said wall, wedging means extending through said apertures in said lugs and through said aperture in said wall, tightening means including a tension bolt and nut adapted to force said wedging means against edges of said apertures in said lugs and an edge of said aperture in said wall to force said casing against said top edge of said wall, a compression spring interposed between said nut and said wedging means, and hydraulic thrust means adapted to be temporarily attached to said bolt and to compress said spring before tightening of said nut.

2. A roller table according to claim 1, wherein said hydraulic thrust means comprises a block adapted to be screwed onto an end of said tension bolt, an annular groove in said block, an annular piston slidingly received in said annular groove, means for admitting fluid under pressure into said groove, and an opening in a side wall of said annular piston providing ac' cess to said nut.

3. A method of securing a bearing casing to a longitudinally extending wall forming part of a frame of a roller table, said casing having a pair of apertured parallel lugs perpendicularly disposed to said bearing axis and straddling the top edge of said wall, and wedging means extending through said lugs and said wall, said method comprising the steps of compressing spring means interposed between a nut on a tension bolt and said wedging device by means of a hydraulic thrust means temporarily attached to said bolt, and tightening said bolt to hold said spring means compressed after removal of said hydraulic thrust means. 

1. A roller table comprising a supporting frame, an apertured longitudinally extending wall on said frame, a number of casings holding bearings each receiving rollers for rotation in said bearings a pair of parallel apertured lugs for each bearing casing disposed perpendicularly to the bearing axis and disposed one on either side the top edge of said longitudinally extending wall with said apertures of said lugs in register with an aperture of said wall, wedging means extending through said apertures in said lugs and through said aperture in said wall, tightening means including a tension bolt and nut adapted to force said wedging means against edges of said apertures in said lugs and an edge of said aperture in said wall to force said casing against said top edge of said wall, a compression spring interposed between said nut and said wedging means, and hydraulic thrust means adapted to be temporarily attached to said bolt and to compress said spring before tightening of said nut.
 2. A roller table according to claim 1, wherein said hydraulic thrust means comprises a block adapted to be screwed onto an end of said tension bolt, an annular groove in said block, an annular piston slidingly received in said annular groove, means for admitting fluid under pressure into said groove, and an opening in a side wall of said annular piston providing access to said nut.
 3. A method of securing a bearing casing to a longitudinally extending wall forming part of a frame of a roller table, said casing having a pair of apertured parallel lugs perpendicularly disposed to said bearing axis and straddling the top edge of said wall, and wedging means extending through said lugs and said wall, said method comprising the steps of compressing spring means interposed between a nut on a teNsion bolt and said wedging device by means of a hydraulic thrust means temporarily attached to said bolt, and tightening said bolt to hold said spring means compressed after removal of said hydraulic thrust means. 